1. Field of the Invention
The present invention relates to imprint lithography templates. More particularly, to imprint lithography templates for use in micro- and nano-imprint lithography processes.
2. Description of the Relevant Art
Optical lithography techniques are currently used to make most microelectronic devices. However, it is believed that these methods are reaching their limits in resolution. Sub-micron scale lithography has been a critical process in the microelectronics industry. The use of submicron scale lithography allows manufacturers to meet the increased demand for smaller and more densely packed electronic components on chips. It is expected that in the coming years, the microelectronics industry will pursue structures that are smaller than about 50 nm. Further, there are emerging applications of nanometer scale lithography in the areas of opto-electronics and magnetic storage. For example, photonic crystals and high-density patterned magnetic memory of the order of terabytes per square inch require nanometer scale lithography.
For making sub-50 nm structures, optical lithography techniques may require the use of very short wavelengths of light (e.g., about 13.2 nm). At these short wavelengths, many common materials may not be optically transparent and therefore imaging systems typically have to be constructed using complicated reflective optics. Furthermore, obtaining a light source that has sufficient output intensity at these wavelengths may be difficult. Such systems may lead to extremely complicated equipment and processes that may be prohibitively expensive. It is believed that high-resolution e-beam lithography techniques, though very precise, may be too slow for high-volume commercial applications.
Imprint lithography processes have demonstrated the ability to replicate high-resolution (sub-50 nm) images on substrates using templates that contain images as topography on their surfaces. It is believed that imprint lithography may be an alternative to optical lithography for use in patterning substrates in the manufacture of microelectronic devices, optical devices, MEMS, opto-electronics, patterned magnetic media for storage applications, etc. Imprint lithography techniques may be superior to optical lithography for making three-dimensional structures such as micro lenses and T-gate structures.
For production-scale imprint lithography, it may be desirable to place patterned regions as close as possible to each other without interfering with subsequent imprints. This effectively maximizes the patternable area on the substrate. In order to accomplish this goal, the location of the any excess fluid that is expelled from the patterned area should be well confined and repeatable. As such, the individual components, including the template, substrate, fluid and any other materials that may affect the physical properties of the system, including but not limited to surface energy, interfacial energies, Haymaker constants, Van der Waals' forces, viscosity, density, opacity, etc., should be engineered properly to accommodate a repeatable process. Accordingly, a need exists for a way of controlling the spread of excess fluid outside desired patterning regions that can facilitate production-scale imprint lithography.